• Journal of Korean Society of Water and Wastewater
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• v.24 no.6
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• pp.723-734
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• 2010

With a belief of high water quality production and less chemical usage, membrane technology including Microfiltration (MF), Ultrafiltration (UF), and Nanofiltration(NF) is being employed more and more in drinking water treatment process. However, due to higher energy consumption of UF and NF, MF is normally used for drinking water treatment especially in a plant of large scale. In this investigation, performance ofsand filtration and membrane filtration was compared regarding removal of various water quality parameters, such as TOC, DOC, KMnO4 consumption, THMFP, and HAAFP. Two lines of pilot plant have been operated, one of which line is a traditional advanced water treatment process which includes sedimentation, sand filtration, ozonation, and activated carbon, and the other line is an alternative treatment process which includes sedimentation with inclined plate, MF membrane, ozonation, and activated carbon. For the first about 4months of period, MF filtration showed similar or little bit higher performance than sand filtration. However, after about 4month later, sand filtration showed much higher performance in removing all parameters monitored in the investigation. It was found that sand filtration is a better option than MF filtration as far as microbial community is fully activated in sand filter bed.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.02a
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• pp.12-27
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• 2004

Pretreatment process consisted of submerged hollow-fiber microfiltration(HMF) membrane and spiral-wound nanofiltration(SNF) membrane has been developed by NETEC, KHNP for the purpose of improving the impurities of liquid radioactive waste before entering Selective Ion Exchange System(SIES). The lab-scale combined system was installed at Kori NPP #2 nuclear power plant and demonstration tests using actual liquid radioactive waste were carried out to verify the performance of the combined system. The submerged HMF membrane was adopted for removal of suspended solid in liquid radioactive waste and the SNF membrane was used for removal of particulate radioisotope such as, Ag-l10m and oily waste because ion exchange resin can not remove particulate radioisotopes. The liquid waste in Waste Holdup Tank (WHT) was processed with HMF and SNF membrane, and SIES. The initial SS concentration and total activity of actual waste were 38,000ppb and $1.534{\times}10_{-3}{\mu}Ci/cc$, respectively. The SS concentration and total activity of permeate were 30ppb and lower than LLD(Lower Limit of Detection), respectively.

• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.740-743
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• 2010

미량의 바나듐을 함유하고 있는 제주도 지하수를 나노여과(nanofiltration) 공정을 이용하여 바나듐을 고농도로 농축하고, 그 농축수를 이용하여 기능성 녹차를 제조하였다. 원수와 4단, 6단 농축한 물의 바나듐 함량은 각각 10.4, 21.6 및 31.7ppb 이었다. 이 농축수들을 이용하여 녹차 제조를 한 결과 바나듐과 카테킨 함량이 감소함을 알 수 있었다. 녹차 추출 전후의 바나듐 함량 감소율은 여름녹차의 경우에는 36.3% - 40.8%, 가을녹차의 경우에는 22.4% - 41.4%이었다. 이는 녹차잎을 이용하여 녹차를 제조하는 과정에서 바나듐 성분이 녹찻잎으로 흡착된 것으로 보이며, 녹차의 카테킨 성분은 이온함량이 높은 물에서는 잘 용출되지 않는다는 것을 확인할 수 있었다.

• Membrane and Water Treatment
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• v.2 no.1
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• pp.1-24
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• 2011

The deficiency of clean water is a major global concern because all the living creatures rely on the drinkable water for survival. On top of this, abundant of clean water supply is also necessary for household, metropolitan inhabitants, industry, and agriculture. Among many purification processes, advances in low-energy membrane separation technology appear to be the most effective solution for water crisis because membranes have been widely recognized as one of the most direct and feasible approaches for clean water production. The aim of this article is to give an overview of (1) two new emerging membrane technologies for water reuse and desalination by forward osmosis (FO) and membrane distillation (MD), and (2) the molecular engineering and development of highly permeable hollow fiber membranes, with polyvinylidene fluoride (PVDF) and polybenzimidazole (PBI) as the main focuses for the aforementioned applications in National University of Singapore (NUS). This article presents the main results of membrane module design, separation performance, membrane characteristics, chemical modification and spinning conditions to produce novel hollow fiber membranes for FO and MD applications. As two potential solutions, MD and FO may be synergistically combined to form a hybrid system as a sustainable alternative technology for fresh water production.

• Membrane and Water Treatment
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• v.5 no.2
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• pp.73-86
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• 2014

Membrane fouling is a major challenge limiting the use of membrane applications. In this study high induced shear rates were utilized at the membrane surface in order to reduce the organic and inorganic scaling by using the torsional vibration of flat sheet membranes. The performances of a vibratory shear-enhanced processing (VSEP) system for the ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membrane filtration of industrial dairy wastewater were investigated. The vibration and non-vibration methods were compared with the same membrane and operational parameters during the purification of real dairy industrial process wastewater. In the initial experiments, short-term tests were carried out in which the effects of vibration amplitude, recirculation flow rate and transmembrane pressure were measured and compared. The permeate flux, turbidity, conductivity and chemical oxygen demand (COD) reduction of dairy wastewater were investigated by using UF, NF and RO membranes with vibration and non-vibration methods. In the subsequent experiments, concentration tests were also carried out. Finally, scanning electron microscopy (SEM) revealed that the vibration method gave a better performance, which can be attributed to the higher membrane shear rate, which reduces the concentration of solids at the membrane, and the transmission.

• Membrane and Water Treatment
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• v.8 no.1
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• pp.1-18
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• 2017

In this study, reuse of biologically treated wastewater of denim washing and dyeing industry has been evaluated by membrane technologies. After that experiments were carried out at laboratory scale in textile dyeing unit by using obtained permeate water samples on 100% cotton based raw fabric belonging to examined industry. During membrane experiments, two different UF (UC100 and UC030) and two different NF (NP010 and NP030) were evaluated under alternative membrane pressures. In permeate water obtained on selected samples, conductivity at the range of $1860-2205{\mu}S/cm$, hardness at the range of 60 to 80 mg/L, total color at the range of 2.4 to 7.6 m-1 and COD at the range of 25-32 mg/L was determined. The following analyzes were performed for the dyed fabrics: perspiration fastness, rub fastness, wash fastness, color fastness to water, color fastness to artificial light, color measurement through the fabric. According to analysis results, selected permeate water have no negative impact on dyeing quality. The study showed that membrane filtration gave good performance for biologically treated textile wastewater, and NF treatment with UF pre-treatment was suitable option for reuse of the effluents.

• Membrane and Water Treatment
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• v.8 no.1
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• pp.89-112
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• 2017

Dyeing wastewaters are the most problematic wastewater in textile industries and also, growing amounts of waste fibers in carpet industries have concerned environmental specialists. Among different treatment methods, membrane filtration processes as energy-efficient and compatible way, were utilized for several individual problems. In this research, novel hybrid membranes were prepared by waste fibers of mechanical carpets as useful resource of membrane matrix and industrial graphite powder as filler to eliminate Chrysophenine GX from dyeing wastewater. These membranes were expected to be utilized for first stage of hybrid membrane filtration process including (adsorption-ultrafiltration) and nanofiltration in Kashan Textile Company. For scaling of membrane filtration process, fouling mechanism of these membranes were recognized and explained by the use of genetic algorithm, as well. The graphite increased rejection and diminished permeate flux at low concentration but in high concentration, the performance was significantly worsened. Among all hybrid membranes, 18% wt. waste fibers-1% wt. graphite membrane had the best performance and minimum fouling. The maximum pore size of this optimum membrane was ranged from 16.10 to 18.72 nm.

• Membrane and Water Treatment
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• v.7 no.6
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• pp.477-493
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• 2016

Immediate use of activated carbon incorporated polysulfone membrane application for dye separation was reported in this work. Dimethylformamide (DMF) was used as the solvent for the membrane preparation. The membrane thus prepared were characterized in terms of surface morphology, ATR-FTIR, AFM, experimental results as membrane performance. The resultant nanofiltration (NF) membranes were tested with Congo red dye concentration 200 mg/L. The water permeability was found to be considerably higher than that reported in literature. Experimental results show that the real rejection of the Congo red is 99.57% over the transmembrane pressure 100 psi using 30% activated carbon incorporated membrane. Prepared NF membranes shows the corresponding permeates fluxes were $40Lm^{-2}h^{-1}$ to $82Lm^{-2}h^{-1}$ with different activated carbon percentage incorporated in polysulfone membrane. The present study demonstrated that dye rejection enhanced NF may be a feasible method for the dye wastewater treatment. The overall observations thus indicated that toxic residual dyes can be appreciably separated from the membrane technology, provided that the accompanying polymeric membrane, activated carbon as binding agents and the process parameter levels are astutely selected.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.04a
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• pp.23-23
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• 1994

환경에 대한 관심이 높아지는 가운데 용존무기염을 효과적으로 분리하기 위한 많은 기술이 연구되고 개발되었다. 이중 막분리를 이용한 무기염의 제거 방법(역삼투법)은 상변화를 수반하지 않는다는 점에서 많은 주목을 받아왔다. 최근들어서는 2가 이상의 염에 대한 선택적 분리 능력을 가지고 있고, 작동압력이 낮아 에너지 소모가 적은 나노여과법(Nanofiltration)이 폐수나 정수처리에 도입되고 있다. 본 연구는 이러한 나노여과법을 이용하여 무기 염을 제거하는 방법에 관한 것이다. 실험에 사용한 분리 막은 Filmtec사의 NF-40, NF-45 두 가지이고 사용한 모듈은 평탄형과 나관형의 두 가지이다. 대상이 되는 폐수는 소석회 처리 단계를 거친 산 폐수로 주로 $Ca^{2+},So_4^{2-}$등의 2가 이온과 Na, Cl등의 1가 이온으로 구성되어 있다. 여기서 $CaSO_4$는 스케일을 형성할 가능성이 크므로 1가 이온에 비해 제거할 필요성이 크지만, 비교적 용해도가 높고 과포화 되는 성질이 커서 처리에 어려움이 있다. 이러한 폐수를 나노여과하였을 때 NF-45 평판평 막의 경우 농축 인자 2.6 부근에서, NF-40 나관평 막의 경우 농축 인자 3 부근에서 막 투과 유속의 급격한 감소가 관찰되었다. 이 때 용액 내 전도도와 용액 내 입자의 분포 변화를 종합하여, 평판형 모듈과 나관형 모듈의 막 오염 현상에 대한 메커니즘을 제시하였다.

• Korean Membrane Journal
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• v.10 no.1
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• pp.13-19
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• 2008

Water softening is a very promising field for membranes and especially ultra low pressure membranes. Nanofiltration membranes based on pore-filling technology was prepared by using a new technique: the in-situ cross-linking. This route involves introducing a pre-formed polymer into the pores of a host membrane and then locking the polymer in the pores by in-situ cross-linking with an appropriate reagent. By this way, it is possible to make robust and competitive, pore-filled, anion-exchange membranes with excellent control over the properties of the incorporated gel without affecting the host membrane. In this paper, the possibilities of tuning such membranes for ultra low pressure water softening was examined by altering pore-filling chemistry (by changing cross-linking and aminating reagents). The results showed that tuning the chemistry of the pore-filling has important effects. In particularly, it had been shown that the correct selection of cross-linking reagent was not only essential to get pore-filled membranes but it could control their properties. Moreover, the aminating reagent could improve membrane performance. It was found that an increase in hydrophobicity could improve the Darcy permeability.